Yasser Omar [email protected]

Total Page:16

File Type:pdf, Size:1020Kb

Yasser Omar Yasser.Omar@Tecnico.Ulisboa.Pt The Revolution of Quantum Information Technologies Yasser Omar [email protected] Physics of Information and Quantum Technologies Group, IT Instituto Superior Técnico, University of Lisbon Y Quantum – Why Quantum Technologies, Ltd. © 2020 Deloitte Central Services, S.A. How can Schrödinger’s cat help us disrupt Information Technologies? Revolutionary idea: Encode information (bits) in quantum systems (atoms, electrons, photons, etc.)! © 2020 Deloitte Central Services, S.A. The qubit or quantum bit =+ 01 0 , 1 |훼|2 + |훽|2 = 1 { | 0 , | 1 }: orthonormal basis Fundamental unit of quantum information. © 2020 Deloitte Central Services, S.A. The qubit or quantum bit =+ 01 0 , 1 |훼|2 + |훽|2 = 1 { | 0 , | 1 }: orthonormal basis Fundamental unit of quantum information. Richer unit, but from which we cannot extract more than one classical bit (Holevo, 1973), and impossible to copy (No-cloning theorem, 1982). A major problem for back-ups and redundancy … but an advantage for security ... © 2020 Deloitte Central Services, S.A. What are qubits good for? Faster computers Quantum Computation Safer communications Quantum Cryptography Better measurements Quantum Sensing and Quantum Metrology © 2020 Deloitte Central Services, S.A. What are qubits good for? Faster computers! Quantum Computation Safer communications Quantum Cryptography Better measurements Quantum Sensing and Quantum Metrology © 2020 Deloitte Central Services, S.A. A Computer is a Calculator and a Simulator Oblivion (UÉvora, IT, …), 2020 today – 20?? © 2020 Deloitte Central Services, S.A. Will Quantum Computing affect your business? Are you ready? © 2020 Deloitte Central Services, S.A. Tackling the biggest of Big Data! Data: 100 Tb/s QuantHEP – Quantum Computing Solutions for High-Energy Physics QuantERA project, 2020-2023 [Member firms and DTTL] - © 2021 (legal entity) Presentation title 9 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] A new frontier for Quantum Computation [Member firms and DTTL] - © 2021 (legal entity) Presentation title 10 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Google & NASA [Member firms and DTTL] - © 2021 (legal entity) Presentation title 11 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] [Member firms and DTTL] - © 2021 (legal entity) Presentation title 12 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Quantum Talent is very hard to find! [Member firms and DTTL] - © 2021 (legal entity) Presentation title 13 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] What are qubits good for? Faster computers Quantum Computation Safer communications! Quantum Cryptography Better measurements Quantum Sensing and Quantum Metrology © 2020 Deloitte Central Services, S.A. Privacy in communications? The Problem: A wants to send a secret message to B. The Characters: CHANNEL A SOURCE RECEIVER B Eavesdropper [Member firms and DTTL] - © 2021 (legal entity) Presentation title 15 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Privacy in communications? The Problem: A wants to send a secret message to B. The Characters: CHANNEL A SOURCE RECEIVER B Eavesdropper Quantum bits offer perfectly secure cryptographic key distribution and communication! [Member firms and DTTL] - © 2021 (legal entity) Presentation title 16 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Quantum Key Distribution Limited to about 100 km in optical fibre (but long enough for a city, or for protecting critical infrastructure, including cabled 5G infrastructure, etc). [Member firms and DTTL] - © 2021 (legal entity) Presentation title 17 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Quantum Key Distribution Limited to about 100 km in optical fibre (but long enough for a city, or for protecting critical infrastructure, including cabled 5G infrastructure, etc). Alternative: satellite quantum communications! [Member firms and DTTL] - © 2021 (legal entity) Presentation title 18 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Quantum Key Distribution Limited to about 100 km in optical fibre (but long enough for a city, or for protecting critical infrastructure, including cabled 5G infrastructure, etc). Alternative: satellite quantum communications! [MemberLimited firms andto DTTL] direct - © 2021-link (legal entity)communications , from A to B. Presentation title 19 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Quantum Internet A Quantum Flagship project to develop a network for quantum communications, for connecting quantum computers, and for connecting quantum sensors. [Member firms and DTTL] - © 2021 (legal entity) Presentation title 20 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Quantum Internet [Member firms and DTTL] - © 2021 (legal entity) Presentation title 21 [To edit, click View > Slide Master > Slide Master] [To edit, click View > Slide Master > Slide Master] Quantum Key Distribution Limited to about 100 km in optical fibre. Limited to direct-link communications, from A to B. Technology not European: IDQ/SKT, China, USA, … QuTe Lab – Quantum Technologies Laboratory IT / IST, inaugurated on 15 Februrary 2019 by Prof. Guilherme de Oliveira Martins, FCGulbenkian © 2020 Deloitte Central Services, S.A. First free-space Quantum Communication in Portugal ! Quantum Key Distribution (BB84) across 180 m., 8 July 2019, campus of Instituto Superior Técnico. © 2020 Deloitte Central Services, S.A. First free-space Quantum Communication in Portugal ! Quantum Key Distribution (BB84) across 180 m., 8 July 2019, campus of Instituto Superior Técnico. © 2020 Deloitte Central Services, S.A. Portable free-space Quantum Communication The same experiment now on the stage of Ciência 2019, 10 July 2019, demonstrating the portability of our setup. © 2020 Deloitte Central Services, S.A. © 2020 Deloitte Central Services, S.A. Do you need premium privacy? Quantum Comms are the only solution! A vision for the future: Portugal signed participation in EuroQCI on 10 July 2019: © 2020 Deloitte Central ServicesEuroQCI, S.A. – European Quantum Communication Infrastructure: connect 600 cities in Europe by 2030. New project QuantSat-PT ! QuantSat-PT – Portuguese Quantum Communications Cube-Satellite Development of the Quantum Payload and Preliminary Design of the Space Segment (2020-2022) PVilloresi QuantSat-PT Part of the QuTe Lab team QuComms in constellations QuantSat-PT is developped in collaboration with the ISTSat-1 IT team. © 2020 Deloitte Central Services, S.A. What are qubits good for? Faster computers Quantum Computation Safer communications Quantum Cryptography Better measurements! Quantum Sensing and Quantum Metrology E.g. geodesy, underground navigation and detection of assets, optical clocks, magnetometry, medical imaging, … © 2020 Deloitte Central Services, S.A. Potential Quantum (undetectable) Radar Quantum Flagship project QMiCS – Quantum Microwave Communication and Sensing © 2020 Deloitte Central Services, S.A. Quantum Information Technologies We want to develop and commercialize: − Quantum computation and simulation for faster information processing − Quantum communications for enhanced privacy − Quantum sensing and metrology with enhanced precision Require a lot of enabling sciences and technologies: Opportunities for classical engineering, control, fabrication, … © 2020 Deloitte Central Services, S.A. Quantum Technologies and Industry © 2020 Deloitte Central Services, S.A. © 2020 Deloitte Central Services, S.A. © 2020 Deloitte Central Services, S.A. © 2020 Deloitte Central Services, S.A. Quantum Technologies at IST & IT 2002: International School on Quantum Computation and Information, IST. 2003: Quantum Computation and Information Seminar, IST. 2006: Security and Quantum Information Group, IT. 2012: Physics of Information & Quantum Technologies Group. 2014: Doctoral Programme in the Physics and Mathematics of Information, IST. 2017: Programa Gulbenkian Novos Talentos em Tecnologias Quânticas. 2019: QuTe Lab – Quantum Technologies Laboratory. 2020: Y Quantum – Why Quantum Technologies, Ltd. 2021: Minor in Quantum Science and Technologies, IST. © 2020 Deloitte Central Services, S.A. Why Quantum Technologies, Ltd. Consulting, Training, & Research The first Portuguese quantum start-up, built on: – Deep knowledge of Quantum Science & Technology (individuals with 20+ years academic experience). – Deep involvement in international research projects (20+ MEuro in competitive funding). – Deep knowledge of the state of the art & emerging trends. – Deep knowledge of the European and international programmes. – Deep knowledge of the community and worldwide experts, and of the emerging talent. Y Quantum: Unique expertise at international level, available for Consulting, Training, and Research. y-quantum.tech © 2020 Deloitte Central Services, S.A. Conclusions Quantum Technologies are Sovereignty Technologies! © 2020 Deloitte Central Services, S.A. Conclusions Quantum Technologies are Sovereignty Technologies! Disruptive information technologies, offering new paradigms: − Quantum computation
Recommended publications
  • Quantum Metrology with Bose-Einstein Condensates
    Submitted in accordance with the requirements for the degree of Doctor of Philosophy SCHOOL OF PHYSICS & ASTRONOMY Quantum metrology with Bose-Einstein condensates Jessica Jane Cooper March 2011 The candidate confirms that the work submitted is her own, except where work which has formed part of jointly-authored publications has been included. The contribution of the candidate and the other authors to this work has been explicitly indicated below. The candidate confirms that the appropriate credit has been given within the thesis where reference has been made to the work of others. Several chapters within this thesis are based on work from jointly-authored publi- cations as detailed below: Chapter 5 - Based on work published in Journal of Physics B 42 105301 titled ‘Scheme for implementing atomic multiport devices’. This work was completed with my supervisor Jacob Dunningham and a postdoctoral researcher David Hallwood. Chapter 6 - Based on work published in Physical Review A 81 043624 titled ‘Entan- glement enhanced atomic gyroscope’. Again, this work was completed with Jacob Dunningham and David Hallwood. Chapter 7 - The research presented in this chapter has recently been added to a pre-print server [arxiv:1101.3852] and will be soon submitted to a peer-reviewed journal. It is titled ‘Robust Heisenberg limited phase measurements using a multi- mode Hilbert space’ and was completed during a visit to Massey University where I collaborated with David Hallwood and his current supervisor Joachim Brand. Chapter 8 - Based on work completed with Jacob Dunningham which has recently been submitted to New Journal of Physics. It is titled ‘Towards improved interfer- ometric sensitivities in the presence of loss’.
    [Show full text]
  • Optimal Adaptive Control for Quantum Metrology with Time-Dependent Hamiltonians
    Optimal adaptive control for quantum metrology with time-dependent Hamiltonians Shengshi Pang1;2∗ and Andrew N. Jordan1;2;3 1Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA 2Center for Coherence and Quantum Optics, University of Rochester, Rochester, New York 14627, USA and 3Institute for Quantum Studies, Chapman University, 1 University Drive, Orange, CA 92866, USA Quantum metrology has been studied for a wide range of systems with time-independent Hamilto- nians. For systems with time-dependent Hamiltonians, however, due to the complexity of dynamics, little has been known about quantum metrology. Here we investigate quantum metrology with time- dependent Hamiltonians to bridge this gap. We obtain the optimal quantum Fisher information for parameters in time-dependent Hamiltonians, and show proper Hamiltonian control is necessary to optimize the Fisher information. We derive the optimal Hamiltonian control, which is generally adaptive, and the measurement scheme to attain the optimal Fisher information. In a minimal ex- ample of a qubit in a rotating magnetic field, we find a surprising result that the fundamental limit of T 2 time scaling of quantum Fisher information can be broken with time-dependent Hamiltonians, which reaches T 4 in estimating the rotation frequency of the field. We conclude by considering level crossings in the derivatives of the Hamiltonians, and point out additional control is necessary for that case. Precision measurement has been long pursued due to particularly in the time scaling of the Fisher information its vital importance in physics and other sciences. Quan- [46], and often requires quantum control to gain the high- tum mechanics supplies this task with two new elements.
    [Show full text]
  • Radiometric Characterization of a Triggered Narrow-Bandwidth Single- Photon Source and Its Use for the Calibration of Silicon Single-Photon Avalanche Detectors
    Metrologia PAPER • OPEN ACCESS Radiometric characterization of a triggered narrow-bandwidth single- photon source and its use for the calibration of silicon single-photon avalanche detectors To cite this article: Hristina Georgieva et al 2020 Metrologia 57 055001 View the article online for updates and enhancements. This content was downloaded from IP address 130.149.177.113 on 19/10/2020 at 14:06 Metrologia Metrologia 57 (2020) 055001 (10pp) https://doi.org/10.1088/1681-7575/ab9db6 Radiometric characterization of a triggered narrow-bandwidth single-photon source and its use for the calibration of silicon single-photon avalanche detectors Hristina Georgieva1, Marco Lopez´ 1, Helmuth Hofer1, Justus Christinck1,2, Beatrice Rodiek1,2, Peter Schnauber3, Arsenty Kaganskiy3, Tobias Heindel3, Sven Rodt3, Stephan Reitzenstein3 and Stefan Kück1,2 1 Physikalisch-Technische Bundesanstalt, Braunschweig, Germany 2 Laboratory for Emerging Nanometrology, Braunschweig, Germany 3 Institut für Festkörperphysik, Technische Universit¨at Berlin, Berlin, Germany E-mail: [email protected] Received 5 May 2020, revised 10 June 2020 Accepted for publication 17 June 2020 Published 07 September 2020 Abstract The traceability of measurements of the parameters characterizing single-photon sources, such as photon flux and optical power, paves the way towards their reliable comparison and quantitative evaluation. In this paper, we present an absolute measurement of the optical power of a single-photon source based on an InGaAs quantum dot under pulsed excitation with a calibrated single-photon avalanche diode (SPAD) detector. For this purpose, a single excitonic line of the quantum dot emission with a bandwidth below 0.1 nm was spectrally filtered by using two tilted interference filters.
    [Show full text]
  • Metrological Complementarity Reveals the Einstein-Podolsky-Rosen Paradox
    ARTICLE https://doi.org/10.1038/s41467-021-22353-3 OPEN Metrological complementarity reveals the Einstein- Podolsky-Rosen paradox ✉ Benjamin Yadin1,2,5, Matteo Fadel 3,5 & Manuel Gessner 4,5 The Einstein-Podolsky-Rosen (EPR) paradox plays a fundamental role in our understanding of quantum mechanics, and is associated with the possibility of predicting the results of non- commuting measurements with a precision that seems to violate the uncertainty principle. 1234567890():,; This apparent contradiction to complementarity is made possible by nonclassical correlations stronger than entanglement, called steering. Quantum information recognises steering as an essential resource for a number of tasks but, contrary to entanglement, its role for metrology has so far remained unclear. Here, we formulate the EPR paradox in the framework of quantum metrology, showing that it enables the precise estimation of a local phase shift and of its generating observable. Employing a stricter formulation of quantum complementarity, we derive a criterion based on the quantum Fisher information that detects steering in a larger class of states than well-known uncertainty-based criteria. Our result identifies useful steering for quantum-enhanced precision measurements and allows one to uncover steering of non-Gaussian states in state-of-the-art experiments. 1 School of Mathematical Sciences and Centre for the Mathematics and Theoretical Physics of Quantum Non-Equilibrium Systems, University of Nottingham, Nottingham, UK. 2 Wolfson College, University of Oxford, Oxford, UK. 3 Department of Physics, University of Basel, Basel, Switzerland. 4 Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, Paris, France. 5These authors contributed equally: Benjamin Yadin, Matteo Fadel, ✉ Manuel Gessner.
    [Show full text]
  • Tensor-Network Approach for Quantum Metrology in Many-Body Quantum Systems
    ARTICLE https://doi.org/10.1038/s41467-019-13735-9 OPEN Tensor-network approach for quantum metrology in many-body quantum systems Krzysztof Chabuda1, Jacek Dziarmaga2, Tobias J. Osborne3 & Rafał Demkowicz-Dobrzański 1* Identification of the optimal quantum metrological protocols in realistic many particle quantum models is in general a challenge that cannot be efficiently addressed by the state-of- the-art numerical and analytical methods. Here we provide a comprehensive framework exploiting matrix product operators (MPO) type tensor networks for quantum metrological problems. The maximal achievable estimation precision as well as the optimal probe states in previously inaccessible regimes can be identified including models with short-range noise correlations. Moreover, the application of infinite MPO (iMPO) techniques allows for a direct and efficient determination of the asymptotic precision in the limit of infinite particle num- bers. We illustrate the potential of our framework in terms of an atomic clock stabilization (temporal noise correlation) example as well as magnetic field sensing (spatial noise cor- relations). As a byproduct, the developed methods may be used to calculate the fidelity susceptibility—a parameter widely used to study phase transitions. 1 Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland. 2 Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland. 3 Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany. *email: [email protected] NATURE COMMUNICATIONS | (2020) 11:250 | https://doi.org/10.1038/s41467-019-13735-9 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-13735-9 uantum metrology1–6 is plagued by the same computa- x fi fl 0 Λ Π (x) Qtional dif culties af icting all quantum information pro- x cessing technologies, namely, the exponential growth of the dimension of many particle Hilbert space7,8.
    [Show full text]
  • Quantum Information Science and Quantum Metrology: Novel Systems and Applications
    Quantum Information Science and Quantum Metrology: Novel Systems and Applications A dissertation presented by P´eterK´om´ar to The Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Physics Harvard University Cambridge, Massachusetts December 2015 c 2015 - P´eterK´om´ar All rights reserved. Thesis advisor Author Mikhail D. Lukin P´eterK´om´ar Quantum Information Science and Quantum Metrology: Novel Systems and Applications Abstract The current frontier of our understanding of the physical universe is dominated by quantum phenomena. Uncovering the prospects and limitations of acquiring and processing information using quantum effects is an outstanding challenge in physical science. This thesis presents an analysis of several new model systems and applications for quantum information processing and metrology. First, we analyze quantum optomechanical systems exhibiting quantum phenom- ena in both optical and mechanical degrees of freedom. We investigate the strength of non-classical correlations in a model system of two optical and one mechanical mode. We propose and analyze experimental protocols that exploit these correlations for quantum computation. We then turn our attention to atom-cavity systems involving strong coupling of atoms with optical photons, and investigate the possibility of using them to store information robustly and as relay nodes. We present a scheme for a robust two-qubit quantum gate with inherent error-detection capabilities. We consider several remote entanglement protocols employing this robust gate, and we use these systems to study the performance of the gate in practical applications. iii Abstract Finally, we present a new protocol for running multiple, remote atomic clocks in quantum unison.
    [Show full text]
  • Observation of Intensity Squeezing in Resonance Fluorescence from a Solid-State Device
    Observation of intensity squeezing in resonance fluorescence from a solid-state device Hui Wang, Jian Qin, Si Chen, Ming-Cheng Chen, Xiang You, Xing Ding, Y.-H. Huo, Ying Yu, C. Schneider, Sven Höfling, Marlan Scully, Chao-Yang Lu, Jian-Wei Pan 1 Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China 2 Shanghai branch, CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China 3 Technische Physik, Physikalisches Instität and Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universitat Würzburg, Am Hubland, D-97074 Würzburg, Germany 4 SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom 5 Institute for Quantum Science and Engineering, Texas A&M University, College Station, Texas 77843, USA 6 Department of Physics, Baylor University, Waco, Texas 76798, USA 7 Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA Abstract Intensity squeezing1—i.e., photon number fluctuations below the shot noise limit—is a fundamental aspect of quantum optics and has wide applications in quantum metrology2-4. It was predicted in 1979 that the intensity squeezing could be observed in resonance fluorescence from a two-level quantum system5. Yet, its experimental observation in solid states was hindered by inefficiencies in generating, collecting and detecting resonance fluorescence. Here, we report the intensity squeezing in a single-mode fibre-coupled resonance fluorescence single- photon source based on a quantum dot-micropillar system.
    [Show full text]
  • Continuous Measurements for Advanced Quantum Metrology †
    proceedings Proceedings Continuous Measurements for Advanced Quantum Metrology † Francesco Albarelli 1,2,* , Matteo A. C. Rossi 2,3 , Dario Tamascelli 2 and Marco G. Genoni 2 1 Department of Physics, University of Warwick, Coventry CV4 7AL, UK 2 Quantum Technology Lab, Dipartimento di Fisica ‘Aldo Pontremoli’, Università degli Studi di Milano, IT-20133 Milan, Italy; matteo.rossi@utu.fi (M.A.C.R.); [email protected] (D.T.); marco.genoni@fisica.unimi.it (M.G.G.) 3 QTF Centre of Excellence, Turku Centre for Quantum Physics, Department of Physics and Astronomy, University of Turku, FI-20014 Turun Yliopisto, Finland * Correspondence: [email protected] † Presented at the 11th Italian Quantum Information Science Conference (IQIS2018), Catania, Italy, 17–20 September 2018. Published: 4 December 2019 Abstract: We review some recent results regarding the use of time-continuous measurements for quantum-enhanced metrology. First, we present the underlying quantum estimation framework and elucidate the correct figures of merit to employ. We then report results from two previous works where the system of interest is an ensemble of two-level atoms (qubits) and the quantity to estimate is a magnetic field along a known direction (a frequency). In the first case, we show that, by continuously monitoring the collective spin observable transversal to the encoding Hamiltonian, we get Heisenberg scaling for the achievable precision (i.e., 1/N for N atoms); this is obtained for an uncorrelated initial state. In the second case, we consider independent noises acting separately on each qubit and we show that the continuous monitoring of all the environmental modes responsible for the noise allows us to restore the Heisenberg scaling of the precision, given an initially entangled GHZ state.
    [Show full text]
  • Adaptive Circuit Learning for Quantum Metrology Ziqi Ma*1, Pranav Gokhale1, Tian-Xing Zheng2, Sisi Zhou2, Xiaofei Yu2, Liang Jiang2, Peter Maurer2, and Frederic T
    Adaptive Circuit Learning for Quantum Metrology Ziqi Ma*1, Pranav Gokhale1, Tian-Xing Zheng2, Sisi Zhou2, Xiaofei Yu2, Liang Jiang2, Peter Maurer2, and Frederic T. Chong †1 1Department of Computer Science, University of Chicago 2Pritzker School of Molecular Engineering, University of Chicago Abstract Quantum advantage is enabled by entanglement, which al- Quantum metrology is an important application of emerging lows for higher sensitivity than what can be achieved by a clas- quantum technologies. We explore whether a hybrid system of sical parallelization of the sensing qubits, called the classical quantum sensors and quantum circuits can surpass the clas- limit. As shown in Figure1, the classical limit gives a square sical limit of sensing. In particular, we use a circuit learning root scaling of Signal-to-Noise Ratio (SNR) versus the number approach to search for encoder and decoder circuits that scal- of sensing qubits. By contrast, the theoretical limit—called ably improve sensitivity under given application and noise the Heisenberg limit—achieves linear scaling [1, 8, 9, 10]. In characteristics. recent years, there has been exciting experimental progress Our approach uses a variational algorithm that can learn beyond the classical limit in areas ranging from spectroscopy a quantum sensing circuit based on platform-specific control [3] to precision measurement [11, 12] to the famous LIGO ex- capacity, noise, and signal distribution. The quantum circuit periment for gravitational wave detection [13, 14]. While the is composed of an encoder which prepares the optimal sensing state-of-the-art shows great promise in achieving quantum ad- state and a decoder which gives an output distribution con- vantage in sensing, we still expect further improvement—the taining information of the signal.
    [Show full text]
  • Experimental Analysis of Einstein-Podolsky-Rosen Steering
    EXPERIMENTALANALYSISOF EINSTEIN-PODOLSKY-ROSENSTEERINGFOR QUANTUMINFORMATIONAPPLICATIONS Von der QUEST-Leibniz-Forschungsschule der Gottfried Wilhelm Leibniz Universität Hannover zur Erlangung des Grades Doktor der Naturwissenschaften -Dr. rer. nat.- genehmigte Dissertation von DIPL.-PHYS.VITUSHÄNDCHEN 2016 Referent : Prof. Dr. rer. nat. Roman Schnabel Institut für Laserphysik, Hamburg Korreferent : Prof. Dr. rer. nat. Reinhard F. Werner Institut für Theoretische Physik, Hannover Tag der Promotion : 04.03.2016 ABSTRACT The first description of quantum steering goes back to Schrödinger. In 1935 he named it a necessary and indispensable feature of quantum mechanics in response to Einstein’s concerns about the completeness of quantum theory. In recent years investigations of the effect have ex- perienced a revival, as it turned out that steering is a distinct subclass of entanglement. It is strictly stronger than genuine entanglement, meaning that all steerable states are entangled but not vice versa, and strictly weaker than the violation of Bell inequalities. Additionally, the violation of a steering inequality has an intrinsic asymmetry due to the directional construction. One party seemingly steers the other and their roles are in general not interchangeable. The first direct ob- servation of this asymmetry is presented in this thesis. It was demon- strated that certain Gaussian quantum optical states show steering from one party to the other but not in the opposite direction. This is a profound result, as the experiment proves that the class of steerable states itself divides into distinct subclasses. Furthermore, steering found major applications in quantum infor- mation. For example in the field of quantum key distribution (QKD) the non-classical correlations can be exploited to establish a secret, cryptographic key.
    [Show full text]
  • Machine Learning for Quantum Phase Estimation
    Machine Learning for Quantum Phase Estimation Nelson Filipe Ferreira de Almeida Costa nelson.fi[email protected] Instituto Superior T´ecnico,Lisboa, Portugal October 2018 Abstract Metrology is the science of the measurement and, as such, encapsulates a wide range of aspects, from defining the units of measurement and realizing them in practice, to the fundamental limits that can be achieved in the precise estimation of parameters. These limits are set by the underlying nature of the measurement scheme. For schemes with independent classical measurement inputs, this limit is defined in metrology by the Standard Quantum Limit (SQL), while for schemes exploring quantum enhancing techniques at the input level, the limit of the measurement precision is set by the Heisenberg Limit (HL). As the employment of quantum enhanced techniques in measurement schemes is still limited by the current level of technology, it is important to develop alternatives to overcome the SQL. Thus, the objective of this work was to devise a quantum phase estimation scheme capable of beating this limit, resorting exclusively to machine learning techniques with a non-entangled input. For this task, two algorithms were studied: Differential Evolution and Particle Swarm Optimization. Under their optimal configurations, both algorithms were applied to an adaptive phase estimation scheme associated to different configurations of the Mach-Zehnder interferometer. Under the ideal and the noisy interferometer configuration the algorithms were able to go beyond the SQL. However for the noisy interferometer with photon loss this was only verified for a certain number of photons. These shortcomings, nevertheless, could be simply overcome by allowing for a larger amount of time for the learning process of the algorithms.
    [Show full text]
  • Complexity Theory and Its Applications in Linear Quantum
    Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2016 Complexity Theory and its Applications in Linear Quantum Optics Jonathan Olson Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Part of the Physical Sciences and Mathematics Commons Recommended Citation Olson, Jonathan, "Complexity Theory and its Applications in Linear Quantum Optics" (2016). LSU Doctoral Dissertations. 2302. https://digitalcommons.lsu.edu/gradschool_dissertations/2302 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. COMPLEXITY THEORY AND ITS APPLICATIONS IN LINEAR QUANTUM OPTICS A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Physics and Astronomy by Jonathan P. Olson M.S., University of Idaho, 2012 August 2016 Acknowledgments My advisor, Jonathan Dowling, is apt to say, \those who take my take my advice do well, and those who don't do less well." I always took his advice (sometimes even against my own judgement) and I find myself doing well. He talked me out of a high-paying, boring career, and for that I owe him a debt I will never be able to adequately repay. My mentor, Mark Wilde, inspired me to work hard without saying a word about what I \should" be doing, and instead leading by example.
    [Show full text]